CN112771725A

CN112771725A - Antenna module, communication device, and array antenna

Info

Publication number: CN112771725A
Application number: CN201980063473.7A
Authority: CN
Inventors: 古樋知重; 有海仁章; 早藤久夫; 加藤知树; 杉本安隆
Original assignee: Murata Manufacturing Co Ltd
Current assignee: Murata Manufacturing Co Ltd
Priority date: 2018-09-27
Filing date: 2019-09-11
Publication date: 2021-05-07
Anticipated expiration: 2039-09-11
Also published as: US20210184344A1; WO2020066604A1; CN112771725B

Abstract

The antenna module (100) includes a dielectric substrate (160) having a multilayer structure, a 1 st radiation electrode (122), a 2 nd radiation electrode (121), and a ground electrode (GND). The 2 nd radiation electrode (121) is disposed between the 1 st radiation electrode (122) and the ground electrode (GND) in the laminating direction of the dielectric substrate (160). A cavity (150) is formed in a dielectric substrate (160) at least partially between a 1 st radiation electrode (122) and a 2 nd radiation electrode (121).

Description

Antenna module, communication device, and array antenna

Technical Field

The present disclosure relates to an antenna module, a communication device, and an array antenna, and more particularly, to a technique for broadband antenna module.

Background

International publication No. 2016/063759 (patent document 1) discloses a patch antenna in which a plurality of planar radiation electrodes (feed elements and passive elements) are stacked.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2016/063759 handbook

Disclosure of Invention

Problems to be solved by the invention

In such an antenna, antenna characteristics such as a bandwidth, a peak gain, and a loss of a high-frequency signal that can be transmitted are affected by a dielectric constant of a dielectric substrate on which an antenna element (radiation electrode) is mounted. In general, the wider the width of the dielectric substrate (i.e., the distance between the radiation electrode and the ground electrode and the distance between the radiation electrodes) is, the wider the width is.

In recent years, in particular, in portable terminals such as smart phones, further thinning is required, and along with this, miniaturization and thinning of the antenna module itself are also required. However, if the dielectric substrate is made thin, there is a problem that the bandwidth of the antenna may be narrowed.

The present disclosure has been made to solve the above-described problems, and an object thereof is to realize a wide band without increasing the size of an antenna module.

Means for solving the problems

The antenna module includes a dielectric substrate having a multilayer structure, a 1 st radiation electrode, a 2 nd radiation electrode, and a ground electrode. The 2 nd radiation electrode is disposed between the 1 st radiation electrode and the ground electrode in the laminating direction of the dielectric substrate. A cavity is formed at least partially between the 1 st radiation electrode and the 2 nd radiation electrode in the dielectric substrate.

ADVANTAGEOUS EFFECTS OF INVENTION

In the antenna module of the present disclosure, a hollow portion is formed at least partially between the stacked two radiation electrodes. With such a configuration, the effective dielectric constant between the two radiation electrodes is reduced as compared with the case of an antenna module having no cavity portion in the dielectric substrate. Therefore, a wide frequency can be achieved without increasing the size of the antenna module.

Drawings

Fig. 1 is a block diagram of a communication device mounted with an antenna module according to embodiment 1.

Fig. 2 is a top view and a cross-sectional view of the antenna module of fig. 1.

Fig. 3 is a diagram for explaining a comparison of antenna characteristics of the antenna modules of embodiment 1 and the comparative example.

Fig. 4 is a plan view and a sectional view of an antenna module according to modification 1.

Fig. 5 is a plan view and a sectional view of an antenna module according to modification 2.

Fig. 6 is a plan view and a sectional view of an antenna module according to modification 3.

Fig. 7 is a plan view and a sectional view of an antenna module according to modification 4.

Fig. 8 is a plan view and a sectional view of an antenna module according to modification 5.

Fig. 9 is a plan view and a sectional view of an antenna module according to modification 6.

Fig. 10 is a plan view and a sectional view of an antenna module according to modification 7.

Fig. 11 is a view 1 for explaining a relationship between a position of the cavity in the Y-axis direction and the bandwidth.

Fig. 12 is a view 2 for explaining the relationship between the position of the cavity in the Y-axis direction and the bandwidth.

Fig. 13 is a view 1 for explaining a relationship between a position of the cavity in the X-axis direction and the bandwidth.

Fig. 14 is a view 2 for explaining the relationship between the position of the cavity in the X-axis direction and the width of the belt.

Fig. 15 is a cross-sectional view of an antenna module according to modification 8.

Fig. 16 is a cross-sectional view of an antenna module according to modification 9.

Fig. 17 is a sectional view of an antenna module according to modification 10.

Fig. 18 is a plan view and a sectional view of an antenna module according to embodiment 2.

Fig. 19 is a plan view and a sectional view of an antenna module according to modification 11.

Fig. 20 is a plan view and a sectional view of an antenna module according to modification 12.

Fig. 21 is a plan view and a sectional view of an antenna module according to modification 13.

Fig. 22 is a plan view and a sectional view of an antenna module according to embodiment 3.

Fig. 23 is a plan view and a sectional view of an antenna module according to modification 14.

Fig. 24 is a plan view and a sectional view of an antenna module according to modification 15.

Fig. 25 is a plan view and a sectional view of an antenna module according to embodiment 4.

Fig. 26 is a top view of the antenna array of embodiment 5.

Fig. 27 is a plan view of the antenna array of modification 16.

Fig. 28 is a plan view and a sectional view of an antenna module according to embodiment 6.

Fig. 29 is a sectional view of an antenna module of a reference example.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and description thereof will not be repeated.

[ embodiment 1]

(basic Structure of communication device)

Fig. 1 is a block diagram of an example of a communication device 10 to which an antenna module 100 according to the present embodiment is applied. The communication device 10 is, for example, a mobile terminal such as a mobile phone, a smart phone, or a tablet computer, a personal computer having a communication function, or the like.

Referring to fig. 1, the communication apparatus 10 includes an antenna module 100 and a bbic (base Band Integrated circuit)200 constituting a baseband signal processing circuit. The antenna module 100 includes an rfic (radio Frequency Integrated circuit)110 and an antenna array 120 as an example of a power supply circuit. The communication device 10 up-converts a signal passed from the BBIC200 to the antenna module 100 into a high-frequency signal and radiates the high-frequency signal from the antenna array 120, and down-converts a high-frequency signal received by the antenna array 120 and performs signal processing by the BBIC 200.

Note that, in fig. 1, for ease of explanation, only the configurations corresponding to 4 radiation electrodes 121 among a plurality of radiation electrodes (antenna elements) 121 constituting the antenna array 120 are shown, and the configurations corresponding to the other radiation electrodes 121 having the same configurations are omitted.

RFIC 110 includes switches 111A to 111D, 113A to 113D, and 117, power amplifiers 112AT to 112DT, low noise amplifiers 112AR to 112DR, attenuators 114A to 114D, phase shifters 115A to 115D, a signal combiner/demultiplexer 116, a mixer 118, and an amplifier circuit 119.

When transmitting a high-frequency signal, switches 111A to 111D and 113A to 113D are switched to the power amplifiers 112AT to 112DT side, and switch 117 is connected to the transmission-side amplifier of amplifier circuit 119. When receiving a high frequency signal, switches 111A to 111D and 113A to 113D are switched to low noise amplifiers 112AR to 112DR, and switch 117 is connected to a receiving-side amplifier of amplifier circuit 119.

The signal delivered from the BBIC200 is amplified by an amplifying circuit 119 and up-converted by a mixer 118. A transmission signal, which is a high-frequency signal obtained by up-conversion, is divided into 4 signals by the signal combiner/splitter 116, and the signals are supplied to the radiation electrodes 121 different from each other through 4 signal paths. In this case, the directivity of the antenna array 120 can be adjusted by independently adjusting the phase shift degrees of the phase shifters 115A to 115D disposed in the respective signal paths.

Further, reception signals, which are high-frequency signals received by the radiation electrodes 121, are multiplexed by the signal multiplexer/demultiplexer 116 via 4 different signal paths. The combined received signal is down-converted by the mixer 118, amplified by the amplifier 119, and transferred to the BBIC 200.

The RFIC 110 is formed as a single-chip integrated circuit component including the above circuit configuration, for example. Alternatively, the devices (switches, power amplifiers, low noise amplifiers, attenuators, and phase shifters) of the RFIC 110 corresponding to the radiation electrodes 121 may be formed as a single-chip integrated circuit component for each corresponding radiation electrode 121.

(Structure of antenna Module)

Fig. 2 is a plan view (upper part) and a sectional view (lower part) of the antenna module 100 according to embodiment 1. Referring to fig. 2, the antenna module 100 includes

radiation electrodes

121 and 122, a dielectric substrate 160, a ground electrode GND, and an RFIC 110. The lower sectional view is a sectional view at a plane II-II passing through a feeding point SP1 of the radiation electrode 121 as a feeding element in the top view. In the following description, the positive direction of the Z axis in fig. 2 is sometimes referred to as the upper surface side, and the negative direction is sometimes referred to as the lower surface side.

In the following description, an example is described in which radiation electrode 121 is a feeding element and radiation electrode 122 is a passive element, but both radiation electrode 121 and radiation electrode 122 may be feeding elements. Alternatively, the radiation electrode 121 may be a passive element and the radiation electrode 122 may be a feeding element.

The dielectric substrate 160 has a substantially rectangular shape when the antenna module 100 is viewed from the normal direction of the dielectric substrate 160 (the Z-axis direction in the figure), and has the 1 st side 161 to the 4 th side 164. In the example of the dielectric substrate 160 shown in FIG. 2, the short sides are the 1 st side 161 and the 3 rd side 163, and the long sides are the 2 nd side 162 and the 4 th side 164. The 2 nd and 4 th edges 162 and 164 are adjacent to the 1 st edge 161. The 3 rd side 163 is opposite the 1 st side 161.

The dielectric substrate 160 has a multilayer structure in which a plurality of dielectric layers are stacked. Each dielectric layer of the dielectric substrate 160 is formed of a resin such as epoxy or polyimide. The dielectric layer may be formed using a Liquid Crystal Polymer (LCP) having a lower dielectric constant, a fluororesin, a Low Temperature Cofired Ceramic (LTCC), or the like. The RFIC 110 is mounted on one principal surface (lower surface) of the dielectric substrate 160 via the solder bump 130.

A plurality of columnar conductors 145 are arranged at predetermined intervals along each side around the dielectric substrate 160. The plurality of columnar conductors 145 are connected to the ground electrode GND inside the dielectric substrate 160. The plurality of columnar conductors 145 function as shields on the side surfaces of the dielectric substrate 160. Note that, in the antenna module described later with reference to fig. 3, the columnar conductor 145 is not described.

The ground electrode GND is disposed at a layer closer to the lower surface of the dielectric substrate 160. The rectangular radiation electrode 122 (1 st radiation electrode) is disposed in a layer closer to the other principal surface (upper surface) of the dielectric substrate 160. Further, a radiation electrode 121 (2 nd radiation electrode) having a rectangular shape is disposed in a layer between the radiation electrode 122 and the ground electrode GND. When the antenna module 100 is viewed from above, the radiation electrode 121 and the radiation electrode 122 overlap each other so that the intersection (i.e., the center) of the diagonal lines of the electrodes coincides with each other. In the example of fig. 2, the radiation electrode 122 is larger than the radiation electrode 121, but the two radiation electrodes may have the same size, or the radiation electrode 121 may be larger.

The radiation electrode 121 is electrically connected to the RFIC 110 via the power feed line 140. Feed line 140 passes through ground electrode GND and is connected to feed point SP1 of radiation electrode 121. Feeding point SP1 is disposed in radiation electrode 121 at a position shifted from the center of radiation electrode 121 toward the 2 nd side 162 along the X axis. Thereby, radio waves polarized in the Y-axis direction are radiated from the radiation electrode 121.

When radiation electrode 122 is a feeding element, feeder line 140 may penetrate radiation electrode 121 and be connected to a feeding point of radiation electrode 122 through a via hole (japanese: ビア) passing through hollow portion 150, for example. Alternatively, power feed line 140 may be connected to radiation electrode 122 via the inside of dielectric substrate 160 while bypassing hollow portion 150.

In the dielectric substrate 160, a cavity 150 is formed in a layer between the radiation electrode 121 and the radiation electrode 122. The dielectric substrate 160 includes a layer (hereinafter also referred to as a "beam") 165 supported by the 1 st side 161 on the upper surface side of the cavity 150, and the radiation electrode 122 is disposed on the beam 165. An opening 152 is formed around the beam portion 165 along the 2 nd to 4 th sides 162 to 164, and the opening 152 penetrates the cavity 150.

In the stacked antenna module in which a plurality of radiation electrodes are stacked as described above, it is known that the bandwidth of the radio wave that can be radiated from the radiation electrode is determined by the strength of the electromagnetic field coupling between the radiation electrode and the ground electrode and the strength of the electromagnetic field coupling between the radiation electrodes. The bandwidth becomes narrower as the strength of the electromagnetic field coupling becomes stronger, and the bandwidth becomes wider as the strength of the electromagnetic field coupling becomes weaker.

In general, in order to increase the bandwidth of the radio wave radiated from the radiation electrode, it is necessary to increase the thickness of the dielectric substrate. On the other hand, in a communication device such as a smartphone to which an antenna module is applied, miniaturization and thinning are required, and therefore, if the thickness of the dielectric substrate is increased, there is a possibility that the miniaturization and thinning of the device are hindered.

Here, the strength of the electromagnetic field coupling is also influenced by the effective dielectric constant between the two electrodes. More specifically, if the effective permittivity is high, the electromagnetic field coupling is strong, and if the effective permittivity is low, the electromagnetic field coupling is weak. That is, the bandwidth can be increased by reducing the effective dielectric constant between the two electrodes.

In the antenna module 100 according to embodiment 1, the hollow portion 150 is formed between the radiation electrode 121 and the radiation electrode 122 as described above. Generally, the dielectric constant of air is lower than that of the dielectric forming the dielectric substrate 160. Therefore, by forming this hollow portion 150, the effective dielectric constant between radiation electrode 121 and radiation electrode 122 can be reduced. As a result, electromagnetic field coupling between the radiation electrode 121 and the radiation electrode 122 can be reduced. Therefore, in the antenna module 100 according to embodiment 1, the bandwidth can be increased without increasing the size of the entire module.

In addition, since the hollow portion 150 is formed, the loss of electric energy in the dielectric body can be reduced, and thus the efficiency of the antenna module can be improved.

(simulation results)

Fig. 3 shows simulation results obtained by comparing antenna characteristics of the antenna module 100 according to embodiment 1 and an antenna module (comparative example) having no cavity portion 150 on a dielectric substrate. In fig. 3, the reflection characteristic (upper part), the gain (middle part), and the efficiency (lower part) at a specific frequency (60.48GHz) are shown.

In the following simulation, an example in which the frequency band used is a millimeter wave frequency band (GHz band) is described, but the configuration of the present disclosure can also be applied to a frequency band other than a millimeter wave.

Referring to fig. 3, in the reflection loss of the comparative example (line LN1A of fig. 3), the band having a reflection loss of less than 10dB is in the range of 55.4 to 69.7GHz (RNG1A), and the bandwidth is 14.3 GHz. On the other hand, in the reflection loss of embodiment 1 (line LN1 in fig. 3), the band having a reflection loss of less than 10dB is in the range of 55.2 to 77.1GHz (RNG1), and the bandwidth is 21.9 GHz. Thus, the bandwidth of the antenna module 100 of embodiment 1 is wider than that of the comparative example.

In the middle gain graph, lines LN2 and LN2A represent gain directivity, and lines LN3 and LN3A represent motion gain. The difference between the gain directivity and the operation gain is the loss of the antenna module. In the gain graph, it is also understood that the range in which the gain directivity is close to the operation gain is the above-described range RNG1A in the comparative example, is the range RNG1 in embodiment 1, and the antenna module 100 of embodiment 1 has low loss in a wide range. Further, the efficiency (the ratio of the radiation power to the input power) at 60.48GHz was 91.4% in the comparative example, and was improved to 94.0% in embodiment 1.

In this way, in the stacked antenna module, the cavity portion is formed between the two radiation electrodes, whereby the bandwidth can be increased and the efficiency can be improved.

(modification example)

Next, with reference to fig. 4 to 10, antenna modules 100A to 100G according to modified examples will be described.

Fig. 4 is a plan view and a sectional view of an antenna module 100A according to modification 1. The antenna module 100A is an example in which the feed point to which the feed line 140 drawn from the RFIC 110 is connected is different from the antenna module 100. Specifically, feeding point SP1A of radiation electrode 121 of antenna module 100A is located at a position shifted from the center of radiation electrode 121 toward 1 st side 161. In the antenna module 100A, the polarization direction of the electric wave radiated from the radiation electrode 121 is the X-axis direction in fig. 4.

Modifications 2 to 5 in fig. 5 to 8 are examples in which the opening 152 on the upper surface of the dielectric substrate 160 is different from the antenna module 100. Specifically, in the antenna module 100B according to modification 2 of fig. 5, the opening 152 is formed only in a portion along the 3 rd side 163, and the beam portion 165 is supported by the 1 st side 161, the 2 nd side 162, and the 4 th side 164.

In the antenna module 100C according to modification 3 of fig. 6, the opening 152 is formed in a portion along the 2 nd and 4

th sides

162 and 164, and the beam portion 165 is supported by the 1 st and 2

nd sides

161 and 162. In the antenna module 100D according to modification 4 of fig. 7, the opening 152 is formed in a portion along two adjacent sides (the 2 nd side 162 and the 3 rd side 163), and the beam 165 is supported by the 1 st side 161 and the 4 th side 164.

Fig. 8 is a plan view and a sectional view of an antenna module 100E according to modification 5. In fig. 8, the lower cross-sectional view is a cross-sectional view along a plane VIII-VIII passing through the power feeding point SP1 and the opening 152. The opening 152 of the antenna module 100E is not in the form of a slit as shown in fig. 5 to 7, but is in the form of a relatively small circle and is formed in the vicinity of the 3 rd side 163. In addition, the number of the openings 152 shown in fig. 8 may be plural, and the formed portions may be different.

In the antenna module 100F of modification 6 of fig. 9 and the antenna module 100G of modification 7 of fig. 10, the cavity 150 is an example of a closed space without an opening portion formed in the upper surface of the dielectric substrate 160.

In the antenna module 100F of fig. 9, the cavity portion 150 is formed in the dielectric substrate 160 so as to overlap with the

entire radiation electrodes

121 and 122 when the antenna module 100F is viewed in a plan view. On the other hand, in the antenna module 100G of fig. 10, the cavity 150 is formed so as to overlap only the portions of the

radiation electrodes

121 and 122 along the 2 nd side 162 and the 4 th side 164 of the dielectric substrate 160.

Here, the relationship between the position of the hollow portion 150 and the bandwidth in the case where the hollow portion 150 overlaps with a partial portion of the radiation electrode as in the antenna module 100G of fig. 10 will be described with reference to fig. 11 to 14.

First, the relationship between the position of the cavity in the Y-axis direction and the bandwidth will be described with reference to fig. 11 and 12. As shown in fig. 11, in the antenna module in which the length of one side of two radiation electrodes (corresponding to the radiation electrodes 121 and 122) is set to 0.9mm and the feeding point is shifted from the center of the radiation electrode in the negative direction of the Y axis, the position of a rectangular hollow portion elongated in the X axis direction and having a dimension of 0.3mm in the Y axis direction is varied in the Y axis direction. Fig. 12 shows the results obtained by simulating the bandwidths obtained at this time.

In fig. 12, the horizontal axis represents the offset amount Yoff by which the center position of the cavity in the Y axis direction is offset from the center position of the radiation electrode in the Y axis direction (X axis in fig. 11), and the vertical axis represents the bandwidth of the radiated radio wave. Line LN10 in fig. 12 is a simulation result of the bandwidth of the comparative example in the case where no cavity is present, and the bandwidth is 6.98 GHz.

Line LN11 in fig. 12 is a simulation result of the bandwidth when the cavity in fig. 11 is varied, and it is understood that a wider bandwidth can be realized between-0.6 and Yoff and 0.6 where the cavity overlaps the radiation electrode, as compared with the case of the comparative example without the cavity. Among them, the bandwidth is large in the vicinity of Yoff of. + -. 0.3.

When a radio wave polarized in the Y-axis direction is radiated as shown in fig. 11, it is known that the electric field intensity generated between two radiation electrodes is generally the largest near the ends of the radiation electrodes in the Y-axis direction. Therefore, by forming the cavity portion in the portion where the electric field intensity is large, the effect of reducing the effective dielectric constant is large, and as a result, the improvement width of the bandwidth is large. On the other hand, in the vicinity of the center of the radiation electrode in the Y-axis direction (Yoff is 0), the electric field intensity is small compared with the end portion in the Y-axis direction, and therefore the improvement effect of the hollow portion on the bandwidth is slightly small.

Next, the relationship between the position of the hollow portion in the X-axis direction and the bandwidth will be described with reference to fig. 13 and 14. In the same manner as in fig. 11, in the antenna module in which the length of one side of the two radiation electrodes is 0.9mm and the polarization direction is the Y-axis direction, the result of simulation of the bandwidth obtained when the position of the rectangular hollow portion elongated in the Y-axis direction with the dimension of 0.3mm in the X-axis direction is varied in the X-axis direction is shown in fig. 14.

The horizontal axis of fig. 14 represents the offset Xoff of the center position of the cavity in the X-axis direction from the center position of the radiation electrode in the X-axis direction (Y-axis of fig. 13) as shown in fig. 13, and the vertical axis represents the bandwidth of the radiated radio wave. A line LN15 in fig. 14 is a simulation result of the bandwidth of the comparative example in the case where the cavity is not present.

Line LN16 in fig. 14 is a simulation result of the bandwidth when cavity 150 in fig. 13 is varied, and it is understood that in this case as well, a wider bandwidth can be realized between-0.6 and Xoff and 0.6 where the cavity and the radiation electrode overlap, as compared with the case of the comparative example. However, unlike the cases of fig. 11 and 12 in which the position in the Y axis direction is varied, the improvement effect of the bandwidth is large near the center of the radiation electrode in the X axis direction (Xoff is 0), and the improvement effect is slightly smaller at the end in the X axis direction than near the center. This is because, as shown in fig. 13, since the feeding point of the radiation electrode is on the Y axis, the electric field generated between the two radiation electrodes is largest near the center of the radiation electrode in the X axis direction.

From the above simulation results, when the hollow portion is partially formed between the two radiation electrodes as in the antenna module 100G of fig. 10, the hollow portion is preferably formed at a position overlapping with the end portion of the radiation electrode in the polarization direction (Y-axis direction), and the hollow portion is preferably formed near the center closer to the feeding point of the radiation electrode in the direction orthogonal to the polarization direction (X-axis direction).

As described above, in the stacked antenna module having two radiation electrodes, the hollow portion is formed at least partially between the two radiation electrodes, whereby the bandwidth of the radiated radio wave can be increased.

The size and position of the cavity 150 and the arrangement of the opening 152 can be determined according to a required bandwidth and the rigidity (durability) of the antenna module.

The hollow portion 150 formed in the dielectric substrate 160 may be divided into a plurality of portions by the wall portion 167 of the dielectric body as in the antenna module 100X of modification 8 of fig. 15. As in the antenna module 100Y of modification 9 of fig. 16, the hollow portion 150 may be formed in the vicinity of the ground electrode GND in the region around the radiation electrode 121 as the feeding element. As in the antenna module 100Z of modification 10 of fig. 17, the cavity 150 may be divided in the stacking direction (thickness direction) of the dielectric substrate 160.

[ embodiment 2]

In embodiment 1, the hollow portion 150 formed inside the dielectric substrate 160 is basically an air layer.

In embodiment 2, an example will be described in which another dielectric material having a dielectric constant lower than that of the dielectric substrate 160 is at least partially filled in the cavity portion 150 formed between the two

radiation electrodes

121 and 122.

Fig. 18 is a plan view and a sectional view of an antenna module 100H according to embodiment 2. In the antenna module 100H, the hollow portion 150 and the opening portion 152 of the antenna module 100 according to embodiment 1 are filled with a dielectric material 170, and the dielectric material 170 has a dielectric constant lower than that of the dielectric material constituting the dielectric substrate 160.

By filling the cavity 150 with different dielectric materials having low dielectric constants in this manner, the effective dielectric constant can be reduced and the bandwidth can be increased as compared with the case where the entire substrate is formed using the same dielectric material. Such a configuration increases the rigidity of the antenna module by a smaller amount than when the cavity 150 is an air layer. In the antenna module 100H, the entire hollow portion 150 is filled with another dielectric material, but only a part of the hollow portion 150 may be filled with another dielectric material.

As in the antenna module 100I of modification 11 of fig. 19, the opening 152 may be filled with a dielectric material 171 different from the dielectric material 170 filling the cavity 150.

In each modification of embodiment 1, the hollow portion 150 may be filled with a dielectric material having a low dielectric constant in the same manner. For example, in the antenna module 100J of modification 12 of fig. 20, the hollow portion 150 of the antenna module 100F of modification 6 of embodiment 1 is filled with another dielectric material 170. In the antenna module 100K according to modification 13 of fig. 21, the hollow portion 150 of the antenna module 100E according to modification 5 of embodiment 1 is filled with another dielectric material 170.

[ embodiment 3]

The antenna module of embodiment 1 has a structure in which two radiation electrodes are stacked, but the number of stacked radiation electrodes may be 3 or more.

In embodiment 3 and its modified examples, an example in which the same configuration as that of embodiment 1 is applied to an antenna module in which 3 radiation electrodes are stacked will be described.

Fig. 22 is a plan view and a sectional view of an antenna module 100L according to embodiment 3. In the antenna module 100L of fig. 22, a radiation electrode 123 (3 rd radiation electrode) as a passive element is added in addition to the radiation electrode 121 as a feeding element and the radiation electrode 122 as a passive element.

The radiation electrode 123 is formed in a layer between the radiation electrode 121 and the radiation electrode 122. In the example of the antenna module 100L, the radiation electrode 122 and the radiation electrode 123 are electrodes having the same size and the same shape, and the radiation electrode 122 and the radiation electrode 123 overlap each other when the antenna module 100L is viewed from above.

A cavity 150 is provided between the radiation electrode 121 and the radiation electrode 123, and the opening 152 penetrates from the upper surface of the dielectric substrate 160 to the cavity 150. The opening 152 of the antenna module 100L is formed along the 2 nd side 162, the 3 rd side 163, and the 4 th side 164 of the antenna module 100L having a rectangular shape in plan view, as in the antenna module 100 of embodiment 1.

Radiation electrodes

122 and 123 as passive elements are arranged on beam portion 165 supported by 1 st side 161.

The layer in which cavity 150 is formed is not limited to the space between radiation electrode 121 and radiation electrode 123. As in the antenna module 100M according to modification 14 of fig. 23, a hollow portion 150 may be formed between radiation electrode 122 and radiation electrode 123.

As in the antenna module 100N according to modification 15 of fig. 24, the hollow portions 150 may be formed between the

radiation electrodes

122 and 123 and between the

radiation electrodes

121 and 123. In the antenna module 100N, the radiation electrode 123 is disposed in the beam portion 166, and the beam portion 166 is formed near the middle portion of the dielectric substrate 160 in the stacking direction.

Although not shown, in embodiment 3, at least a part of the cavity portion 150 may be filled with a different dielectric material having a lower dielectric constant than the dielectric material constituting the dielectric substrate 160 as in embodiment 2.

In the antenna module in which 3 or more radiation electrodes are stacked as described above, the hollow portion is formed between any of the radiation electrodes, whereby the bandwidth of the radiated radio wave can be increased.

[ embodiment 4]

In each of the antenna modules described in embodiments 1 to 3, the beam portion 165 on which the radiation electrode 122 as a passive element is disposed has a structure including the upper surface of the dielectric substrate 160.

However, in the structure in which the hollow portion is an air layer and the opening portion penetrates to the upper surface of the dielectric substrate, the portion supporting the beam portion is limited, and therefore, there is a possibility that the supporting portion of the beam portion is damaged by a force applied when the antenna module is handled or the like.

Thus, in embodiment 4, the beam portion on which the radiation electrode is arranged is formed so as to be supported at a position shifted in the stacking direction from the uppermost surface of the dielectric substrate. With such a configuration, the possibility of directly applying an external force to the beam portion during processing is reduced, and breakage of the beam portion is suppressed.

Fig. 25 is a plan view and a sectional view of an antenna module 100P according to embodiment 4. As shown in the cross-sectional view, the beam portion 165A is formed at a position offset from the upper surface of the dielectric substrate 160 in the negative direction of the Z axis (i.e., on the side of the cavity portion 150) in the antenna module 100P. In other words, the height of the peripheral portion of the dielectric substrate 160 is higher than the height of the upper surface of the beam portion 165A. For example, in the case of a stacked antenna module, the other antenna module is likely to contact the peripheral portion of the dielectric substrate 160, but with such a configuration, the beam portion 165A is less likely to be directly subjected to an external force. This can suppress breakage of the beam portion 165A.

In the example of the antenna module 100P in fig. 25, the entire height of the portion around the dielectric substrate 160 is higher than the height of the upper surface of the beam portion 165A, but the entire height of the portion around the dielectric substrate 160 does not have to be as high as a wall. For example, the following structure is also possible: the uppermost surface of the dielectric substrate 160 is higher than the upper surfaces of the beam portions 165A by partially disposing the columnar dielectric around the dielectric substrate 160.

[ embodiment 5]

Embodiments 1 to 4 describe the case of an antenna module including a single antenna element and an RFIC. In embodiment 5, a case of an array antenna in which antenna elements are arrayed will be described.

Fig. 26 is a plan view of the array antenna 300 according to embodiment 5. The array antenna 300 has a structure in which 4 antenna modules 100-1 to 100-4 having the same structure as the antenna module 100 described in embodiment 1 are arranged in a 2 × 2 array. The number of antenna modules forming the array is not limited to 4, and may be 2, 3, or 5 or more.

In the array antenna 300, a cavity is formed between the radiating electrodes in each antenna module, so that the bandwidth of the radiated radio wave can be increased. In addition, although not shown, in the case of an array antenna, the RFIC may be provided for each antenna module, or one RFIC may be provided for a plurality of antenna modules.

In the case of an array antenna, the hollow portions may be communicated with each other by removing the wall of the dielectric body between the adjacent antenna blocks.

Fig. 27 is a plan view of an array antenna 300A according to modification 16. In the array antenna 300A, the wall between the adjacent antenna module 100-1A and antenna module 100-3A is removed, and the hollow portions of the two antenna modules communicate with each other. The hollow portion of the adjacent antenna module 100-2A communicates with the hollow portion of the antenna module 100-4A. In the example of fig. 27, the wall of the end portion of each antenna module in the Y axis direction is also removed.

In this way, by making the hollow portions of the adjacent antenna blocks communicate with each other in the array antenna, the dielectric portion can be reduced, the effective dielectric constant can be further reduced, and the bandwidth can be further increased.

[ embodiment 6]

In embodiment 6, the following structure is explained: in a so-called dual band antenna module capable of radiating radio waves of two frequency bands, a cavity is formed in a dielectric substrate, thereby increasing the bandwidth of the radiated radio waves.

Fig. 28 is a plan view and a sectional view of an antenna module 100Q according to embodiment 6. Referring to fig. 28, the antenna module 100Q includes a radiation electrode 121 as a feeding element and a radiation electrode 124 as a passive element. The radiation electrode 121 is disposed in an inner layer closer to the upper surface of the dielectric substrate 160. The radiation electrode 124 is disposed opposite to the radiation electrode 121 on the lower surface side of the radiation electrode 121, that is, between the radiation electrode 121 and the ground electrode GND.

Two power feeding points SP1 and SP2 are disposed in the radiation electrode 121. When antenna module 100Q is viewed from above, feeding point SP1 is located at a position shifted from the center of radiation electrode 121 in the negative direction of the Y axis. The high frequency signal from the RFIC 110 is transmitted to the power supply point SP1 through the power supply line 141. When a high-frequency signal is supplied to the feeding point SP1, a radio wave polarized in the Y-axis direction is radiated.

In addition, in a plan view of the antenna module 100Q, the feeding point SP2 is disposed at a position shifted from the center of the radiation electrode 121 in the positive direction of the X axis. The high frequency signal from the RFIC 110 is transmitted to the power supply point SP2 through the power supply line 142. When a high-frequency signal is supplied to the power feeding point SP2, a radio wave polarized in the X-axis direction is radiated. That is, the antenna module 100Q is also a dual-polarization type antenna module capable of radiating radio waves of two different polarization directions.

The feed lines 141 and 142 pass through the radiation electrode 124 from the RFIC 110 to reach the radiation electrode 121. Therefore, a radio wave is radiated from the radiation electrode 124 by supplying a high-frequency signal corresponding to the resonance frequency of the radiation electrode 124 as a passive element to the

power supply lines

141 and 142.

The size of the radiation electrode 124 is larger than that of the radiation electrode 121, and the resonance frequency of the radiation electrode 124 is lower than that of the radiation electrode 121. Therefore, radio waves of a lower frequency band than the radiation electrode 121 are radiated from the radiation electrode 124.

In antenna module 100Q, hollow portion 155 is formed in the layer between radiation electrode 121 and radiation electrode 124. In a plan view of the antenna module 100Q, the cavity 155 has substantially the same shape as the radiation electrode 121 and is formed at a position overlapping the radiation electrode 121.

Radiation electrode 121 functions as an antenna by generating electric flux lines with radiation electrode 124. Therefore, the antenna characteristics are affected due to the effective dielectric constant between the radiation electrode 121 and the radiation electrode 124. In the antenna module 100Q, since the cavity 155 is formed in the layer between the radiation electrode 121 and the radiation electrode 124 as described above, the effective dielectric constant is lower than that in the case where the cavity 155 is filled with a dielectric material. This can reduce electromagnetic field coupling between the radiation electrode 121 and the radiation electrode 124, and can expand the bandwidth of the radio wave radiated from the radiation electrode 121.

The bandwidth of the electric wave radiated from the radiation electrode 124 is affected due to the effective dielectric constant between the radiation electrode 124 and the ground electrode GND. Therefore, even if hollow portion 155 is formed between radiation electrode 121 and radiation electrode 124, the bandwidth of the radio wave radiated from radiation electrode 124 does not substantially change. That is, by forming hollow portion 156 between radiation electrode 121 and radiation electrode 124, the bandwidth of the radio wave radiated from radiation electrode 121 can be increased while maintaining the bandwidth of the radio wave radiated from radiation electrode 124.

On the other hand, when the bandwidth of the radio wave radiated from the radiation electrode 124 is increased, the hollow portion 156 can be formed in the layer between the radiation electrode 124 and the ground electrode GND as in the antenna module 100R shown in the reference example of fig. 29.

Further, although not shown, when the bandwidth of both the radio wave radiated from the radiation electrode 121 and the radio wave radiated from the radiation electrode 124 is widened, the hollow portion can be formed in the layer between the radiation electrode 121 and the radiation electrode 124 and between the radiation electrode 124 and the ground electrode GND.

In the antenna module of fig. 28 and 29, the

feeder lines

141 and 142 are partially inserted into the hollow portion in the longitudinal direction, but the feeder lines in the hollow portion may be formed by connecting, for example, a columnar conductor to a via hole or a feeder element formed in the dielectric layer using silver paste or the like. Alternatively, the power supply lines in the hollow portion may be formed by stacking flat small electrodes in the thickness direction. When the power feeding line and the power feeding element in the hollow portion are connected, a method of connecting the power feeding line to a structure in which the power feeding element is formed in advance in the dielectric layer is adopted, so that the flatness of the power feeding element can be ensured as compared with a case where the power feeding element is connected to the power feeding element solely.

In the antenna module 100Q of fig. 28 and the antenna module 100R of fig. 29, the

cavity portions

155 and 156 may be divided in the stacking direction of the dielectric substrate 160 in the same manner as in fig. 17.

As described above, in the dual band antenna module in which two radiation electrodes are stacked and which can radiate radio waves of different frequency bands, the hollow portion is formed in the layer between the two radiation electrodes and/or the layer between the low frequency side radiation electrode and the ground electrode, whereby the bandwidth of each radio wave can be independently adjusted.

The embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not by the description of the embodiments described above, and all modifications within the meaning and scope equivalent to the claims are intended to be included.

Description of the reference numerals

10. A communication device; 100. 100A-100N, 100P-100R, 100X-100Z, antenna module; 110. an RFIC; 111A to 111D, 113A to 113D, 117, and a switch; 112AR to 112DR, a low noise amplifier; 112 AT-112 DT, power amplifier; 114A to 114D, an attenuator; 115A to 115D, phase shifters; 116. a signal synthesizer/demultiplexer; 118. a mixer; 119. an amplifying circuit; 120. an antenna array; 121 to 124, a radiation electrode; 130. brazing the bumps; 140 to 142, a power supply line; 145. a columnar conductor; 150. 155, 156, a hollow portion; 152. an opening part; 160. a dielectric substrate; 161-164, side; 165. 165A, 166, a beam portion; 167.

wall portions

170, 171, a dielectric material; 300. 300A, an array antenna; GND, ground electrode; SP1, SP1A, SP2, power supply point.

Claims

1. An antenna module, wherein,

the antenna module includes:

a dielectric substrate having a multilayer structure;

a 1 st radiation electrode;

a ground electrode; and

a 2 nd radiation electrode disposed between the 1 st radiation electrode and the ground electrode in a lamination direction of the dielectric substrate,

in the dielectric substrate, a cavity is formed at least partially between the 1 st radiation electrode and the 2 nd radiation electrode.

2. The antenna module of claim 1,

the entire 1 st radiation electrode and the entire 2 nd radiation electrode overlap the cavity portion when the dielectric substrate is viewed in a plan view.

3. The antenna module of claim 1 or 2,

an opening portion penetrating from an upper surface of the dielectric substrate to the cavity portion is formed in the dielectric substrate.

4. The antenna module of claim 3,

the dielectric substrate is formed in a substantially rectangular shape having a 1 st side, a 2 nd side, a 3 rd side and a 4 th side,

the dielectric substrate includes a beam portion supported by the 1 st side of the dielectric substrate and on which the 1 st radiation electrode is disposed,

the opening is formed along the 2 nd to 4 th sides around the beam portion.

5. The antenna module of claim 4,

the 2 nd edge is an edge adjacent to the 1 st edge,

the 2 nd radiation electrode is a power supply element,

in a case where the antenna module is viewed in plan, a feeding point of the 2 nd radiation electrode is disposed at a position shifted from a center of the 2 nd radiation electrode toward the 2 nd side.

6. The antenna module of claim 3,

said 1 st edge being opposite said 3 rd edge,

the dielectric substrate includes a beam portion supported by the 1 st and 3 rd sides of the dielectric substrate and on which the 1 st radiation electrode is disposed,

the opening is formed along the 2 nd side and the 4 th side around the beam portion.

7. The antenna module of claim 3,

said 2 nd and said 4 th edges are edges adjacent to said 1 st edge, said 3 rd edge is an edge opposite to said 1 st edge,

the dielectric substrate includes a beam portion supported by the 1 st side, the 2 nd side, and the 4 th side of the dielectric substrate and on which the 1 st radiation electrode is disposed,

the opening is formed along the 3 rd side around the beam portion.

8. The antenna module of any one of claims 4-7,

the beam portion is formed at a position shifted from the upper surface of the dielectric substrate toward the cavity portion in the stacking direction.

9. The antenna module of any one of claims 1-8,

the cavity portion overlaps at least a part of an end portion of the 1 st radiation electrode in a polarization direction of a radio wave radiated from the antenna module when the antenna module is viewed in plan.

10. The antenna module of any one of claims 1-9,

the 1 st radiation electrode is a passive element, and the 2 nd radiation electrode is a power supply element.

11. The antenna module of any one of claims 1-10,

the antenna module further includes a 3 rd radiation electrode disposed between the 1 st radiation electrode and the 2 nd radiation electrode in a lamination direction of the dielectric substrate,

the cavity portion is formed at least one of between the 1 st radiation electrode and the 3 rd radiation electrode and between the 2 nd radiation electrode and the 3 rd radiation electrode.

12. The antenna module of any one of claims 1-11,

at least a part of the cavity portion is filled with a dielectric material having a lower dielectric constant than the dielectric substrate.

13. The antenna module of any one of claims 1-12,

the dielectric substrate includes a plurality of columnar conductors arranged along a periphery of the dielectric substrate.

14. The antenna module of any one of claims 1-13,

the antenna module further includes a power supply circuit that supplies high-frequency power to the power supply element of the antenna module.

15. A communication apparatus, wherein,

the communication device is provided with the antenna module according to any one of claims 1 to 14.

16. An array antenna, wherein,

the 1 st antenna module and the 2 nd antenna module are adjacently disposed,

the 1 st antenna module and the 2 nd antenna module respectively include:

a dielectric substrate having a multilayer structure;

a 1 st radiation electrode;

a ground electrode; and

17. The array antenna of claim 16,

the cavity of the 1 st antenna module is communicated with the cavity of the 2 nd antenna module.